ok im having major problems with my 17" powerbook. it was sleeping and when i opened the lid, nothing happened, screen was black and it would do nothing. I held the power button down and it restarted. But I couldnt get it to boot. I did a safe boot and got in and got all my data. I repaired all my permissions and everything and ran a bunch of disk utilities and couldnt get it to boot still. The weird thing is, a lot of times after a restart the screen will stay black well after the turn on chime. When i bang it on the back, above the battery, sometimes the screen starts and attempts to boot. The apple logo will show and the litttle rotating sun, which freezes halfway through. I have managed to get a hardware test in (after having to bang the bottom for the screen to turn on). Everything passed. I tried zapping the pram, after the third chime, the screen still wouldnt come on. I eventually erased the entire disk and reinstalled jaguar ( i was running panther before). After it installed, i got the welcome screen , and began registration and halfway through it froze. I hit in on the back again and I got a kernel panic. I restarted and restarted and restarted and got it going again, and it froze during registration again. I reinstalled jaguar again and still cant get anywhere. I really don't know if banging on the back is doing anything or if it is a weird coincidence. Sometimes when its frozen on the startup screen and it freezes, it will unfreeze after i hit it.. only to freeze again shortly. What can i do???